Learning XPath becomes easier with a tool like the Interactive XPath Expression Builder 4.0, created by Aaron Skonnard. Import your XML file and begin executing XPath expressions in a matter of seconds. What I like about this tool is the ability to see the XML input, and to highlight nodes as the correct XPath expressions select them. I wish I found this tool sooner; it would have shortened the learning curve of XSLT and XPath.

Get access to the Interactive XPath Expression Builder 4.0 at PluralSite.com, or download it here here